In recent days, many Americans have reveled in the hypocrisy of a number of well-known people revealed as subscribers to the Ashley Madison pro-adultery website. But there is a far more important revelation from the hackings: the alarming number who signed up for the site—33 million people. That startling statistic reminds us that no one is immune to sexual temptation. It also shows how far modern society has drifted from the idea that marriage is a permanent and exclusive union.

Some people may be inclined to blame the breakdown of marriage on gays and lesbians, but as the Ashley Madison hack should make clear, heterosexuals are to blame for the breakdown of marriage.

Long before there was a debate about same-sex anything, far too many heterosexuals bought into a bad liberal ideology about sexuality that came out of the sexual revolution. It was heterosexuals in the ’60s and ’70s who began to live as if marriage should last only as long as the romantic feelings last, replacing “as long as we both shall live” with “as long as we both shall love.” If what makes a marriage is merely consenting adult romance, then there is no reason why marriage has to be permanent or limited to two persons, much less sexually exclusive.

As a result, cohabitation, no-fault divorce, extramarital sex, non-marital childbearing, pornography, and the hook-up culture became normalized, and each contributed to the breakdown of the marriage culture. Same-sex marriage didn’t cause any of these problems. Ashley Madison didn’t cause these problems. The redefinition and the website are, rather, the logical conclusion of these problems. The problem is that these conclusions follow a train of logic that begins from utterly false premises.

And it is on these “love = love” false premises that Justice Kennedy based his Supreme Court opinion redefining marriage throughout our nation. After all, the legal redefinition of marriage could take place only after 50 years of a cultural redefinition—with all of the broken hearts and broken homes that it has left in its wake.

It is a mistake to think that the redefinition of marriage will make matters better—it will only make them worse. That’s because redefining marriage into a genderless, romantic institution doubles down on a mistaken vision of human sexuality that says consenting adults should do whatever consenting adults want to do. That love equals love, of whatever variety—gender or number of partners or length of time—we prefer. Indeed, leading LGBT activists have even suggested that extramarital sex should be normalized, and that gay marriage could teach heterosexuals the virtue of such arrangements.

Andrew Sullivan, for example, argues that the “openness” of same-sex unions could enhance the bonds of husbands and wives: “among gay male relationships, the openness of the contract makes it more likely to survive than many heterosexual bonds. … [T]here is more likely to be greater understanding of the need for extramarital outlets between two men than between a man and a woman. … [It] could undoubtedly help strengthen and inform many heterosexual bonds.”

The gay activist Dan Savage agrees. A 2011 New York Times Magazineprofile of Savage, headlined “Married, with Infidelities,” introduced Americans to the term “monogamish”—relationships in which partners allow sexual infidelity provided they are honest about it. The article explains: “Savage says a more flexible attitude within marriage may be just what the straight community needs.” After all, sexual exclusivity “gives people unrealistic expectations of themselves and their partners.”

So if you object to Ashley Madison because of the secrecy and deception, an adultery website such as OpenMinded.com, that facilitates honest so-called “ethical cheating,” may be for you.

This makes a certain sort of sense once you get rid of the idea that marriage is about uniting a man and a woman as husband and wife, in a permanent, exclusive bond, to then be mother and father to any children their union may produce. If marriage is just about consenting adult romance, it’s hard to argue against OpenMinded.com and monogamish options.

Changing our legal—and thus further changing our cultural—understanding of marriage will impact society as a whole. As our law teaches a falsehood about marriage, it will be even harder for people to live out the truth of marriage.

And so, as people internalize this new vision of marriage, marriage will be less and less a stabilizing force. The history of the last 50 years of cultural redefinition demonstrates exactly this. The legal redefinition will simply lock it in, increase the damage, and make recovery even more difficult.

But if fewer people live out the norms of exclusivity and permanence in marriage, then fewer people will reap the benefits of the institution of marriage—not only spouses, but also children. Preserving the man-woman definition of marriage is the only way to preserve the benefits of marriage as an exclusive and permanent institution. How can the law teach that fathers are essential, for instance, when it has officially made them optional?

The Ashley Madison scandal should be cause for all of us to reconsider the importance of marriage. And while gays and lesbians certainly aren’t to blame for the collapse of our marriage culture, redefining marriage is both a symptom and, most likely, a cause of future deterioration.